The present invention relates to racket stringing apparatus and pertains particularly to an improved apparatus having automatic uniform tensioning means.
The stringing of tennis rackets and the like is a time consuming process requiring extremely accurate tensioning of the strings in order to suit the racket to the individual player. Many types of machines and apparatus for stringing of rackets is known in the art. One successful type, however, is that shown in U.S. Pat. No. 3,441,275, issued Apr. 29, 1969. This apparatus, while satisfactory in many respects, does have a number of drawbacks. These and other prior art devices fail to maintain the proper tension under certain circumstances. For example, when cross stringing between strings already in position, the string can be pulled with sufficient tension; yet due to friction between the strings, may be slightly curved. When the curve is taken out of the string, slack in the string automatically results, which is not then compensated by the tensioning device.
Another problem with the prior art devices is that the clamping means frequently permits slack to result in the strings. This is due in part to the construction of the string holding clamps which are such that any wear results in permitting the clamp to either tilt or slightly move when tension is applied thereto resulting in a loss of the optimum tension in the string.
Still other problems include the difficulty of locating and manipulating the string holding clamps during the stringing operation. Such prior art construction provide for several different mounting positions of clamps for holding the strings. However, this requires multiple clamps and/or multiple mounting means for the clamps.
A further problem with prior art devices is the tension head clamp is complicated and expensive to construct and inconvenient to operate.
Still further problems of the prior art devices include the inability of the tension apparatus to maintain a predetermined continuous tension in the string, regardless of any slack that may be imposed thereon. Such devices are also complicated and difficult to operate and maintain.
Accordingly it is desirable that an improved racket stringing mechanism be available which has improved tensioning apparatus for applying and maintaining a predetermined tension on the strings and automatically taking up any slack that may develop therein and having improved clamping means which is simple and easy to operate and avoids the problems of slack as in the prior art.